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There are 2 polar icecaps, Antarctica and Greenland, and if all the ice they held was melted into the ocean then the sea level would rise more than 60m, enough to cover most of Hobart. Don’t worry though. Even if that were to happen (and no serious scientist thinks it will), it would take hundreds of years for all of that ice to melt.
A much harder question to answer is how much of the polar icecaps are likely to melt, and what will happen then? Since 2006 global sea level has risen about 48 mm, about 22% from Greenland melt and 13% from Antarctica. Although Greenland is melting faster at the moment, there is much more ice in Antarctica, and in fact understanding how much Antarctic ice will melt in the future is one of the biggest questions in climate science. As well as increasing the size of the ocean, adding all that fresh (non-salty) water may change the way that the ocean
currents move water between the surface and deep ocean, which could impact sea life and the rest of the climate.
Scientists are working hard to better understand how the icecap will change in the future, both by visiting Antarctica to take measurements, and by building better computer models. In the meantime, it’s important that we take action to limit warming in Antarctica as much as possible.
What and interesting question! We asked three scientists what they'd be doing if climate change didn't exist.
This is a great question – which has several parts to it. If we stop putting large amounts of greenhouse gasses that cause climate change (like carbon dioxide and methane) into the atmosphere, it would still take several decades for warming to slow down and stop. This is because the high levels of these gases already in the atmosphere will take a long time to breakdown (in the case of methane) or be absorbed into the ocean and forests (in the case of carbon dioxide). Sea level will also continue to rise for many decades, even if we stop emitting these gases today. Stopping carbon dioxide emissions would help slow down ocean acidification, benefiting marine life and fisheries.
If climate change itself were to suddenly stop – which would be great if you had a magic wand – there are some positive things that would happen. The Earth would stop warming, and we would no longer experience the increasing temperatures and heatwaves associated with climate change. The rate of sea-level rise would also slow down. Melting glaciers and ice sheets, which are major contributors to sea-level rise, would decrease their rate of melting. The Arctic region, which has experienced significant ice loss, would start to recover. Sea ice would become more stable, which is important for the functioning of polar ecosystems. If climate change stopped completely tomorrow, many ecosystems that have been disrupted by climate change, such as coral reefs, forests, and polar environments, would have a better chance of recovering.
There would be good things that are very important to humans. Stopping climate change could improve food security by reducing crop failures and the negative impacts on agriculture caused by intense floods and droughts. Human health risks would also be reduced, as there would be less exposure to extreme heat – and many people can die during intense heatwaves.
It's important to note that while these are positive outcomes, stopping climate change would not necessarily reverse the effects that have already occurred. Many changes to ecosystems and landscapes are irreversible, and some consequences, such as the loss of certain species, may be permanent. Furthermore, global climate change is a complex process, and a sudden stop could also have unintended consequences. I hope you can think of some of these unintended consequences!
A carbon footprint is the total amount of greenhouse gases (the cause of climate change) that are generated by what we do. The carbon footprint will differ among individuals depending on their location, behaviour, and personal choices. Differences in carbon footprint between two people could come from, for example:
When calculating a carbon footprint, it is important to include both direct and indirect emissions. For example, driving a non-electric car produces direct emissions from the use of fuel by the car, while using a computer produces indirect emissions from the use of electricity generated at a power station that uses fossil fuel. Similarly, a piece of paper or an apple (or anything we buy/consume) will likely have associated indirect emissions from the production and transport of the product.
Calculating your carbon footprint can be challenging but there are several online calculators that may help you to calculate emissions from various sources. Some examples are the Carbon Footprint Calculator For Individuals And Households or the ClimateHero Carbon Calculator.
It can be very frustrating to witness the slow pace of action by governments to limit climate change, particularly when we look at the record of the current Australian Federal Government. But Australia did once have a very effective climate policy. Julia Gillard's government introduced the Clean Energy Act, which put a price on carbon emissions, and operated from 2012-2013. This reduced carbon emissions by the biggest polluting companies by 7%. But the price on carbon only lasted one year because Australians voted to replace the Labor Gillard government with a Coalition government under Tony Abbott, who repealed the Act.
Since then, Australia has not had an effective national climate policy. But several state governments, local governments and and some companies have introduced their own policies. The Tasmanian Government is now legislating that Tasmania will have a Net Zero carbon emissions by 2030.
Momentum is building and we still have a small window of opportunity for our governments to make systemic change to limit global climate change to 1.5 or 2 degrees Celcius.
What are the things that make governments act on climate change?
Great question! Greta Thunberg started learning about climate change at school when she was just eight years old and her class watched documentaries about climate change. What she learnt stuck with her, and she became worried about the future and frustrated that people in power were not doing enough about it. When she was very young, she started making more sustainable choices in her life, including not eating meat or travelling by airplane.
Greta has Asperger's syndrome, which is a condition on the autism spectrum, and she now talks about it as her superpower as a climate activist. From a very young age, she had a strong sense of what was right and wrong, and knew that if we were going to save the planet, humans have to act now.
It was this sense of right and wrong about the environment, and her anger at world leaders ignoring the climate crisis, that led her to start protesting, starting with the Swedish government. In August 2018, when she was 15 years old, she didn't go to school and sat down outside the Swedish Parliament with a sign that read 'School Strike for Climate' and some information about climate change. She posted about her strike on social media, and slowly but surely, people came to join her in Sweden, and then around the world.
Greta now is a fierce climate activist and continues to fight for climate action and climate justice. One of the best things about her story is that she did not start out trying to become famous or start a worldwide movement, but instead she chose something that she could do in her own life. Just by taking a small action, she inspired other people to take action too. Anybody can be a Greta, just start small and stick with it!
Hmm, that’s an interesting (and slightly scary) question. The only reason that Earth may ‘explode’ is if a meteorite the size of the moon impacted the Earth. Large meteorites have impacted Earth before, for example 66 million years ago and that meteorite was probably at least 10-80 km in diameter. That impact caused the outpouring of huge volumes of hot liquid magma in lots of places on Earth’s surface and changed Earth’s climate. The dinosaurs and many reptiles couldn’t cope with those changes and became extinct, which then enabled the mammals to flourish.
Here in Tasmania we also have craters associated with the impact of Meteorites – for example Darwin Crater in southwest Tasmania. That impact was probably around 820,000 years ago.
Interestingly, scientists are now using sediment cores taken from the Darwin crater to find out how the climate changed more than 20,000 years ago.
Your question is very important to answer. I want to answer it because I have been interested in and worked on managing the interaction of people with the Earth for as long as I can remember. At your age, I was asking what the world was like before people and what difference we have made, good and bad. What a tough question. And 1.5 degrees does not seem like much, does it? Your question is so important that the Intergovernmental Panel on Climate Change (IPCC) devoted a whole special report of 630 pages in 2018 to this question. The answer I give is only a snippet of what you might wish to learn.
What does it mean to have a 1.5 degree Celsius temperature rise? This means that the average surface temperature (across all land, sea, and ice) of the Earth will have risen by 1.5 degrees since pre-industrial times. Pre-industrial times were times when the impacts people had on the Earth were very small and local to where they lived.
Because this is the average whole-Earth-surface temperature increase, the increase in average temperature will be different in different places – hot, dry areas will become hotter and drier. Cool, wet areas will become warmer and may either become drier or wetter depending on where they are. Frozen areas will become ice-free. The tropics will become places difficult to live in, for people, animals, and plants. The polar environments will reduce and may disappear in some places. This is happening now with the bleaching of coral reefs, the burning of rainforests, the drying of the continents and the reduction of ice-dependent systems, particularly in the Arctic and in the highest mountain ranges. And the sea level is rising. Thus, an average increase of the Earth’s temperature even before we reach 1.5 degrees can have wide ranging effects because of this variation around the Earth.
According to the IPCC, the Earth will not be doomed when the average temperature of the Earth goes past 1.5 degrees but, increasingly, life will become very different to what we are used to and, for many people, animals and plants, it will become very much harder to live (thousands of species are expected to go extinct as a result and many people will die). Our dreams and stories about life on the Earth will more and more become memories of past days rather than opportunities for experiencing in the future. But why would that be?
There are two very important factors to consider. The first is how rapidly and how far the sea level will rise. In Tasmania, many low-lying areas with townships (e.g. Kingston Beach) will become more frequently flooded, to the point when insurance companies will no longer insure houses for damage. Who will pay for those people to move their homes? Where will they go? More significantly, many low lying countries will become uninhabitable because of sea-level rise and floods. The people from those countries will need to move. How many millions of people will that be? Where will they go? Will they be helped to relocate? How understanding will the world be to people forced out of their homes?
The second factor is what a warmer atmosphere and ocean will do? Communities and livelihoods built on or around ice (permafrost, glaciers, snow) will reduce and possibly disappear. The IPCC has well established that the frequency and intensity of extreme weather events will increase. Increased storms and floods will compound the impacts of sea level rise as well as disrupt ports, coastal airstrips, roads, electricity grids and so on. But it is not just about storms and floods, it is also about heat waves and droughts. Hotter and longer heat waves will result in more people dying from heat stress. Longer and more frequent droughts will mean farms, grasslands and forests will become much drier and more difficult to sustain. This will lead to starvation and lack of water in many communities. In Australia, our Great Artesian Basin that gives water to so many of our rural communities will begin to dry up. Some of the more sensitive areas will be lost, like the Great Barrier Reef.
Limiting warming to 1.5 degrees will give us a greater chance of restoring the world to what we know and love. The greater the Earth warms the longer the impacts of that warming will last – rather than the effects of warming remaining until the end of the century it is likely to remain long after that time. Many scientists fear that if the Earth warms beyond 2 degrees then it may reach tipping points from which we cannot return to what we know. How can we believe this will happen when we have not experienced these levels of warming? The IPCC has well established mathematical models able to assess the nature of the climate, weather and state of the physical Earth system. These models have been tested in many ways to ensure they can be validly used to assess what the world will be like. These models then are used to determine what might happen to farms, forests, cities and ocean systems. For Tasmania, this has been done in a Climate Futures Tasmania project, which was one of the first projects globally to undertake these kinds of assessments to help communities and governments better plan and adapt to the future.
Can you believe these results? Ask your parents or grandparents how reliable the weather forecasts were during their childhood. Compare that to the forecasts we have now when we can plan at least four days in advance for what the weather will be like. These forecasts are based on atmospheric models, the same kind of models used for climate assessments.
Great question! It’s an extremely difficult question to answer, but I will do my best! There are more than nine million species of animal on Earth, and many more that we are yet to discover! However, I think all species will be affected by climate change – for some, the effects will be beneficial… But I suspect that most of the species we cherish will be negatively affected. I know one study looked at 538 plant and animal species around the globe. The study found that between 57 – 70% of these species may face extinction because of anthropogenic climate change (unnatural levels of change attributed to human activity). In fact, the first mammal to go extinct due to climate change has already been recorded – and it was an Australian species: The Bramble Cay Melomy.
In Australia, we are also witnessing the drastic effects of chytrid (pronounced ‘kit-rid') fungus. This fungus can occupy areas above a certain temperature, and as the climate warms, it increases its range. Unfortunately, it is deadly to frogs and other amphibians – coating their skin and making it difficult for them to breathe. It can also affect their nervous system and change their behaviour. Chytrid fungus has caused the decline of more than 40 Australian frog species. Of these, seven are now extinct.
As a marine scientist, I am most familiar with the issues faced by animals living in the ocean. One consequence of increased carbon emissions is the acidification of our oceans. When carbon dioxide combines with seawater, chemical reactions occur that produce carbonic acid. This is bad news for creatures that have shells (sea-snails, urchins, oysters, etc.), as the materials they use to form their shell have been degraded by acid. This means they have less protection from environmental conditions and usually means they cannot survive. If small animals like urchins do not survive, then animals that feed on urchins (like sea-otters) have no food and begin to starve.
Another marine-related consequence of climate change is to do with the rise in global average temperature. Some species, such as sea-turtles and crocodiles, require specific nest temperatures for the breeding season. This is because the temperature of the nest determines how many males and how many females will hatch from their eggs! For example, Green Sea-Turtles generally hatch as males if the nest temperature remains below 29 degrees Celsius, and hatch as females if the nest temperature is above 31 degrees Celsius. Temperatures between 29 and 31 tend to produce a mix of male and female hatchlings. As the temperature rises, we are seeing fewer males hatch, which means there will be fewer breeding opportunities and fewer babies hatching in the future. However, it is also worth noting if a nest gets too hot (above 36 degrees Celsius), then the turtles won’t hatch, and the nest fails. This would be dire for sea-turtle species.
Before finishing this answer, I want to emphasise that there are solutions to the climate crisis, and people around the world are working towards them. We can, and we will, avoid the worst of climate change. Whilst inevitable, the outcomes do not need to be the same as our current projections. Renewable energy solutions are becoming cheaper every day, and though Australia might seem a laggard on climate action, the international sector is collaborating and moving quickly towards a reduction in global emissions. Chile is rapidly phasing out coal power, and along with South Africa, Chile invests the most in renewable energy relative to their GDP. China is the world’s largest producer of wind energy and is working hard to meet its energy demands. The United States of America is seeking to reduce its own emissions by 50% by 2030. The world is listening to the science, and though it can feel slow at times, the wheels of progress are turning.
It is increasingly recognised that the current level of global funding in climate mitigation (reducing global emissions) and adaptation (disaster mitigation through minimisation of exposure and/or vulnerability to climate hazards) is nowhere near that needed to achieve the transition to a sustainable, net zero emissions and resilient world. Funding needs to increase drastically everywhere to meet this need.
At the moment, climate funding everywhere is focussed on supporting mitigation activities to reduce emissions, via renewable energy investment and shifting high emitting industries such as transport to low emission alternatives. Adaptation activities account for less than 10% of total available funding.
Measuring how well countries are adapting to climate change is very difficult, but we can measure how much countries have reduced their emissions. Other countries have been able to reduce their emissions more than Australia. CO2 emissions in the UK were almost 50% lower in 2020 than in 1990. Germany, Russia, and France have also managed to substantially reduce their emissions. The US were about 11% lower. In contrast, Australia’s emissions increased by approximately 40% over this period. China and India have seen an over 300% increase in emissions over this period associated with their economic growth.
Whilst China’s emissions have grown substantially, they are spending the most money of anywhere to reduce this. Almost a third of climate funding is spent in China, which has led to China’s production being much more efficient than in the past.
Climate funding in Australia is much lower. Less than 2% of global climate funding occurs in Australia, NZ and PNG combined.
This year, Australia updated its climate change commitments, pledging to reduce greenhouse gas emissions by 43% below 2005 levels by 2030. This compares to commitments by 2030 of other countries (US: 50-52% below 2005 levels; China 60-65% below 2005 levels; UK 68% below 1990 levels; EU: 55% below 1990 levels).
Australia has also this year announced major programs that will support adaptation activities, and we hope will improve Australia’s ability to withstand future climate disasters.
Further reading:
Naran, B. et al. Global Landscape of Climate Finance 2021 (Climate Policy Initiative, 2021).
Crippa, M., Solazzo, E., Huang, G. et al. High resolution temporal profiles in the Emissions Database for Global Atmospheric Research. Sci Data 7, 121 (2020). https://doi.org/10.1038/s41597-020-0462-2
